define(function() {
    // Regular Expressions for parsing tags and attributes
    var startTag = /^<([-A-Za-z0-9_]+)((?:\s+[@a-zA-Z_:][-a-zA-Z0-9_:.]*(?:\s*=\s*(?:(?:"[^"]*")|(?:'[^']*')|[^>\s]+))?)*)\s*(\/?)>/,
        endTag = /^<\/([-A-Za-z0-9_]+)[^>]*>/,
        attr = /([@a-zA-Z_:][-a-zA-Z0-9_:.]*)(?:\s*=\s*(?:(?:"((?:\\.|[^"])*)")|(?:'((?:\\.|[^'])*)')|([^>\s]+)))?/g;

    // Empty Elements - HTML 5
    var empty = makeMap("area,base,basefont,br,col,frame,hr,img,input,link,meta,param,embed,command,keygen,source,track,wbr");

    // Block Elements - HTML 5
    var block = makeMap("a,address,article,applet,aside,audio,blockquote,button,canvas,center,dd,del,dir,div,dl,dt,fieldset,figcaption,figure,footer,form,frameset,h1,h2,h3,h4,h5,h6,header,hgroup,hr,iframe,ins,isindex,li,map,menu,noframes,noscript,object,ol,output,p,pre,section,script,table,tbody,td,tfoot,th,thead,tr,ul,video");

    // Inline Elements - HTML 5
    var inline = makeMap("abbr,acronym,applet,b,basefont,bdo,big,br,button,cite,code,del,dfn,em,font,i,iframe,img,input,ins,kbd,label,map,object,q,s,samp,script,select,small,span,strike,strong,sub,sup,textarea,tt,u,var");

    // Elements that you can, intentionally, leave open
    // (and which close themselves)
    var closeSelf = makeMap("colgroup,dd,dt,li,options,p,td,tfoot,th,thead,tr");

    // Attributes that have their values filled in disabled="disabled"
    var fillAttrs = makeMap("checked,compact,declare,defer,disabled,ismap,multiple,nohref,noresize,noshade,nowrap,readonly,selected");

    // Special Elements (can contain anything)
    var special = makeMap("script,style");

    var utils = {};

    var HTMLParser = function (html, handler) {
        var index, chars, match, stack = [], last = html;
        stack.last = function () {
            return this[this.length - 1];
        };

        while (html) {
            chars = true;

            // Make sure we're not in a script or style element
            if (!stack.last() || !special[stack.last()]) {

                // Comment
                if (html.indexOf("<!--") == 0) {
                    index = html.indexOf("-->");

                    if (index >= 0) {
                        if (handler.comment)
                            handler.comment(html.substring(4, index));
                        html = html.substring(index + 3);
                        chars = false;
                    }

                    // end tag
                } else if (html.indexOf("</") == 0) {
                    match = html.match(endTag);

                    if (match) {
                        html = html.substring(match[0].length);
                        match[0].replace(endTag, parseEndTag);
                        chars = false;
                    }

                    // start tag
                } else if (html.indexOf("<") == 0) {
                    match = html.match(startTag);

                    if (match) {
                        html = html.substring(match[0].length);
                        match[0].replace(startTag, parseStartTag);
                        chars = false;
                    }
                }

                if (chars) {
                    index = html.indexOf("<");

                    var text = index < 0 ? html : html.substring(0, index);
                    html = index < 0 ? "" : html.substring(index);

                    if (handler.chars)
                        handler.chars(text);
                }

            } else {
                html = html.replace(new RegExp("([\\s\\S]*?)<\/" + stack.last() + "[^>]*>"), function (all, text) {
                    text = text.replace(/<!--([\s\S]*?)-->|<!\[CDATA\[([\s\S]*?)]]>/g, "$1$2");
                    if (handler.chars)
                        handler.chars(text);

                    return "";
                });

                parseEndTag("", stack.last());
            }

            if (html == last)
                throw "Parse Error: " + html;
            last = html;
        }

        // Clean up any remaining tags
        parseEndTag();

        function parseStartTag(tag, tagName, rest, unary) {
            tagName = tagName.toLowerCase();

            if (block[tagName]) {
                while (stack.last() && inline[stack.last()]) {
                    parseEndTag("", stack.last());
                }
            }

            if (closeSelf[tagName] && stack.last() == tagName) {
                parseEndTag("", tagName);
            }

            unary = empty[tagName] || !!unary;

            if (!unary)
                stack.push(tagName);

            if (handler.start) {
                var attrs = [];

                rest.replace(attr, function (match, name) {
                    var value = arguments[2] ? arguments[2] :
                        arguments[3] ? arguments[3] :
                        arguments[4] ? arguments[4] :
                        fillAttrs[name] ? name : "";

                    attrs.push({
                        name: name,
                        value: value,
                        escaped: value.replace(/(^|[^\\])"/g, '$1\\\"') //"
                    });
                });

                if (handler.start)
                    handler.start(tagName, attrs, unary);
            }
        }

        function parseEndTag(tag, tagName) {
            // If no tag name is provided, clean shop
            if (!tagName)
                var pos = 0;

                // Find the closest opened tag of the same type
            else
                for (var pos = stack.length - 1; pos >= 0; pos--)
                    if (stack[pos] == tagName)
                        break;

            if (pos >= 0) {
                // Close all the open elements, up the stack
                for (var i = stack.length - 1; i >= pos; i--)
                    if (handler.end)
                        handler.end(stack[i]);

                // Remove the open elements from the stack
                stack.length = pos;
            }
        }
    };

    utils.HTMLtoXML = function (html) {
        var results = "";

        HTMLParser(html, {
            start: function (tag, attrs, unary) {
                results += "<" + tag;

                for (var i = 0; i < attrs.length; i++)
                    results += " " + attrs[i].name + '="' + attrs[i].escaped + '"';
                results += ">";
            },
            end: function (tag) {
                results += "</" + tag + ">";
            },
            chars: function (text) {
                results += text;
            },
            comment: function (text) {
                results += "<!--" + text + "-->";
            }
        });

        return results;
    };

    utils.HTMLtoDOM = function (html, doc) {
        // There can be only one of these elements
        var one = makeMap("html,head,body,title");

        // Enforce a structure for the document
        var structure = {
            link: "head",
            base: "head"
        };

        if (!doc) {
            if (typeof DOMDocument != "undefined")
                doc = new DOMDocument();
            else if (typeof document != "undefined" && document.implementation && document.implementation.createDocument)
                doc = document.implementation.createDocument("", "", null);
            else if (typeof ActiveX != "undefined")
                doc = new ActiveXObject("Msxml.DOMDocument");

        } else
            doc = doc.ownerDocument ||
                doc.getOwnerDocument && doc.getOwnerDocument() ||
                doc;

        var elems = [],
            documentElement = doc.documentElement ||
                doc.getDocumentElement && doc.getDocumentElement();

        // If we're dealing with an empty document then we
        // need to pre-populate it with the HTML document structure
        if (!documentElement && doc.createElement) (function () {
            var html = doc.createElement("html");
            var head = doc.createElement("head");
            head.appendChild(doc.createElement("title"));
            html.appendChild(head);
            html.appendChild(doc.createElement("body"));
            doc.appendChild(html);
        })();

        // Find all the unique elements
        if (doc.getElementsByTagName)
            for (var i in one)
                one[i] = doc.getElementsByTagName(i)[0];

        // If we're working with a document, inject contents into
        // the body element
        var curParentNode = one.body;

        HTMLParser(html, {
            start: function (tagName, attrs, unary) {
                // If it's a pre-built element, then we can ignore
                // its construction
                if (one[tagName]) {
                    curParentNode = one[tagName];
                    if (!unary) {
                        elems.push(curParentNode);
                    }
                    return;
                }

                var elem = doc.createElement(tagName);

                for (var attr in attrs)
                    elem.setAttribute(attrs[attr].name, attrs[attr].value);

                if (structure[tagName] && typeof one[structure[tagName]] != "boolean")
                    one[structure[tagName]].appendChild(elem);

                else if (curParentNode && curParentNode.appendChild)
                    curParentNode.appendChild(elem);

                if (!unary) {
                    elems.push(elem);
                    curParentNode = elem;
                }
            },
            end: function (tag) {
                elems.length -= 1;

                // Init the new parentNode
                curParentNode = elems[elems.length - 1];
            },
            chars: function (text) {
                curParentNode.appendChild(doc.createTextNode(text));
            },
            comment: function (text) {
                // create comment node
            }
        });

        return doc;
    };

    function makeMap(str) {
        var obj = {}, items = str.split(",");
        for (var i = 0; i < items.length; i++)
            obj[items[i]] = true;
        return obj;
    }

    utils.HTMLParser = HTMLParser;

    return utils;
});